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Troubleshooting

File descriptor limits​

In some cases, file descriptor limits may cause errors like "Too many open files". To solve that, see the instructions for your platform below.

To increase the limits for the user running Nethermind (given the process name of nethermind), run:

sudo echo "nethermind soft nofile 100000" > /etc/security/limits.d/nethermind.conf
sudo echo "nethermind hard nofile 100000" >> /etc/security/limits.d/nethermind.conf

Database corruption issues​

Database corruption is one of the issues that happen now and then; it has many possible causes among them:

  • Hardware failures: disk failures, memory errors, hardware overheating, etc.
  • Power cuts and abrupt shutdowns

There's no shortcut in such situations, and resyncing Nethermind from scratch is the recommended remedy.

TrieNodeException errors​

If Nethermind reports Nethermind.Trie.TrieNodeException or Nethermind.Trie.MissingTrieNodeException errors, that usually indicates database corruption or missing data. The following steps may help:

  • If the node is still syncing, wait until it has been fully synced and observe for errors
  • Restart the node and observe for errors
  • Update to the latest version of Nethermind
  • If the above steps fail, a resync may be required

Issues with lock files​

If Nethermind complains about the lock files, it perhaps because of one of the following:

  • Another Nethermind process is running using the same database

  • The database has not been appropriately closed on the last run.
    In this case, run the following command from the Nethermind database directory:

    find . -type f -name 'LOCK' -delete

Block checksum mismatch​

Sometimes Nethermind may fail with an error similar the following:

Corruption: block checksum mismatch: expected 2087346143, got 2983326672 in...

This tends to happen on XFS file systems under very high memory pressure. The issue can be mitigated by using the --Db.UseDirectIoForFlushAndCompactions true option although at the cost of performance.

However, quite often, this is because of memory module issues.

Plugin loading failure​

If Nethermind fails to start with a message like Failed to load plugin..., this is most likely due to a missing or incompatible plugin. Reinstalling Nethermind usually fixes the issue.

tip

If you install Nethermind over an existing installation, remove the old installation first, particularly the plugins directory. Package managers do this automatically.

Watch out not to accidentally delete the database directory with the sync data, if any.